1. Field of the Invention
The present invention relates generally to electric motors having a horizontal axis, such as open drip-proof motors, used in outdoor environments, such as to power a swimming pool pump. More specifically, the present invention concerns a fluid deflecting baffle secureable to an endshield of such a motor that includes a liquid flow obstructing louver with a generally flat liquid deflection surface disposed at an oblique angle relative to the axis of the motor.
2. Discussion of the Prior Art
Those of ordinary skill in the art will appreciate that electric motors need to be protected from outside contaminants in order to function properly. In particular, electric motors that are used in outdoor environments, such as open drip proof motors, need to protect the internal motor components from contaminants (e.g., rain, other liquids, or debris), which could otherwise damage the motor. It is known that continued exposure to contaminants, particularly water or other liquids, can cause corrosion and wear to the internal motor components (e.g., the rotor or stator windings), sometimes leading to a premature failure of the motor. For motors that are used outdoors, exposure to water or other liquids can come not only from vertical rainfall, but also from rain that is blown significantly horizontally, spray from a hose, irrigating sprinklers, and other such sources.
Those of ordinary skill in the art will also appreciate, however, that these electric motors, like many electric devices, generate heat during operation and thus need to be cooled during operation. One effective method as cooling is to use a fan to force a flow of air through the motor in a generally axial venting direction. Consequently, vent openings in the motor case are required, and the case cannot be entirely sealed from outside contaminants. In a horizontal open drip proof motor, intake vent openings are often located in the lower margins of the endshield of the motor case. A typical way to improve convection and increase heat dissipation within the case is to use the fan to increase the velocity of the cooling airflow. Conventionally, one of two methods of using airflow to cool a motor is used, either a pressure fan system (direct mode) or a reverse airflow fan system (RAF).
In the pressure fan system, cooling air is forced from the front of the motor (the side from which the shaft projects) axially through the motor case and out of the back of the motor. Conversely, in the reverse airflow fan system, the blades of the fan are reversed such that air is pulled from the back of the motor axially through the motor case and exhausts at the front of the motor. The reverse airflow fan system creates a more significant vacuum than does the pressure fan system, leading to effective cooling. However, the combination of a stronger vacuum created by a larger pressure differential and the pulling of air from the back of the motor (often more exposed to outside elements) can leave openings on the back intake side of the motor particularly susceptible to water or other liquid entry.
In a traditional reverse airflow fan system, a cover that overhangs the vent opening but is otherwise open below is secured to the endshield on the back of the motor to insulate electrical components and to prevent vertical rainfall from passing through the vent opening. Such prior art covers have been satisfactory in some respects, but these covers also suffer drawbacks as they allow liquids that may flow in a generally axial direction (from sources such as those identified above) to pass through the open area of the cover and directly into the motor case. Once such liquid enters the motor case, the liquid can condense on the internal motor components, detrimentally shortening the effective life of the motor as described above.
The prior art does not include a cover for use in a reverse airflow fan system that accomplishes both effective deflection of axially flowing liquid while also permitting sufficient axial flowing venting air to effectively cool the motor.